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/*
* Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*/
#include <linux/cpu.h>
#include <linux/kvm_host.h>
#include <linux/preempt.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/bootmem.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/sizes.h>
#include <asm/cputable.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include "book3s_hv_cma.h"
/*
* Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
* should be power of 2.
*/
#define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */
/*
* By default we reserve 5% of memory for hash pagetable allocation.
*/
static unsigned long kvm_cma_resv_ratio = 5;
/*
* We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area.
* Each RMA has to be physically contiguous and of a size that the
* hardware supports. PPC970 and POWER7 support 64MB, 128MB and 256MB,
* and other larger sizes. Since we are unlikely to be allocate that
* much physically contiguous memory after the system is up and running,
* we preallocate a set of RMAs in early boot using CMA.
* should be power of 2.
*/
unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT; /* 128MB */
EXPORT_SYMBOL_GPL(kvm_rma_pages);
/* Work out RMLS (real mode limit selector) field value for a given RMA size.
Assumes POWER7 or PPC970. */
static inline int lpcr_rmls(unsigned long rma_size)
{
switch (rma_size) {
case 32ul << 20: /* 32 MB */
if (cpu_has_feature(CPU_FTR_ARCH_206))
return 8; /* only supported on POWER7 */
return -1;
case 64ul << 20: /* 64 MB */
return 3;
case 128ul << 20: /* 128 MB */
return 7;
case 256ul << 20: /* 256 MB */
return 4;
case 1ul << 30: /* 1 GB */
return 2;
case 16ul << 30: /* 16 GB */
return 1;
case 256ul << 30: /* 256 GB */
return 0;
default:
return -1;
}
}
static int __init early_parse_rma_size(char *p)
{
unsigned long kvm_rma_size;
pr_debug("%s(%s)\n", __func__, p);
if (!p)
return -EINVAL;
kvm_rma_size = memparse(p, &p);
/*
* Check that the requested size is one supported in hardware
*/
if (lpcr_rmls(kvm_rma_size) < 0) {
pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
return -EINVAL;
}
kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
return 0;
}
early_param("kvm_rma_size", early_parse_rma_size);
struct kvm_rma_info *kvm_alloc_rma()
{
struct page *page;
struct kvm_rma_info *ri;
ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
if (!ri)
return NULL;
page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
if (!page)
goto err_out;
atomic_set(&ri->use_count, 1);
ri->base_pfn = page_to_pfn(page);
return ri;
err_out:
kfree(ri);
return NULL;
}
EXPORT_SYMBOL_GPL(kvm_alloc_rma);
void kvm_release_rma(struct kvm_rma_info *ri)
{
if (atomic_dec_and_test(&ri->use_count)) {
kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
kfree(ri);
}
}
EXPORT_SYMBOL_GPL(kvm_release_rma);
static int __init early_parse_kvm_cma_resv(char *p)
{
pr_debug("%s(%s)\n", __func__, p);
if (!p)
return -EINVAL;
return kstrtoul(p, 0, &kvm_cma_resv_ratio);
}
early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
struct page *kvm_alloc_hpt(unsigned long nr_pages)
{
unsigned long align_pages = HPT_ALIGN_PAGES;
/* Old CPUs require HPT aligned on a multiple of its size */
if (!cpu_has_feature(CPU_FTR_ARCH_206))
align_pages = nr_pages;
return kvm_alloc_cma(nr_pages, align_pages);
}
EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
void kvm_release_hpt(struct page *page, unsigned long nr_pages)
{
kvm_release_cma(page, nr_pages);
}
EXPORT_SYMBOL_GPL(kvm_release_hpt);
/**
* kvm_cma_reserve() - reserve area for kvm hash pagetable
*
* This function reserves memory from early allocator. It should be
* called by arch specific code once the early allocator (memblock or bootmem)
* has been activated and all other subsystems have already allocated/reserved
* memory.
*/
void __init kvm_cma_reserve(void)
{
unsigned long align_size;
struct memblock_region *reg;
phys_addr_t selected_size = 0;
/*
* We cannot use memblock_phys_mem_size() here, because
* memblock_analyze() has not been called yet.
*/
for_each_memblock(memory, reg)
selected_size += memblock_region_memory_end_pfn(reg) -
memblock_region_memory_base_pfn(reg);
selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
if (selected_size) {
pr_debug("%s: reserving %ld MiB for global area\n", __func__,
(unsigned long)selected_size / SZ_1M);
/*
* Old CPUs require HPT aligned on a multiple of its size. So for them
* make the alignment as max size we could request.
*/
if (!cpu_has_feature(CPU_FTR_ARCH_206))
align_size = __rounddown_pow_of_two(selected_size);
else
align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
kvm_cma_declare_contiguous(selected_size, align_size);
}
}
/*
* When running HV mode KVM we need to block certain operations while KVM VMs
* exist in the system. We use a counter of VMs to track this.
*
* One of the operations we need to block is onlining of secondaries, so we
* protect hv_vm_count with get/put_online_cpus().
*/
static atomic_t hv_vm_count;
void kvm_hv_vm_activated(void)
{
get_online_cpus();
atomic_inc(&hv_vm_count);
put_online_cpus();
}
EXPORT_SYMBOL_GPL(kvm_hv_vm_activated);
void kvm_hv_vm_deactivated(void)
{
get_online_cpus();
atomic_dec(&hv_vm_count);
put_online_cpus();
}
EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated);
bool kvm_hv_mode_active(void)
{
return atomic_read(&hv_vm_count) != 0;
}
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